Weatherstrips in the past have been produced by several processes, and in one process a skin of rubber is positioned in a die cavity, a quantity of unfoamed rubber (natural or synthetic) placed within the skin, a base of hard rubber applied, the die is closed, and the product is moulded. This is a tedious and expensive operation and to improve productivity it has been known to extrude a sponge simultaneously with a base section of dense rubber through a dual extrusion head, adhering the two together before curing. In this respect the reader's attention is drawn to the Applicant's Australian Patent No. 291,754 (corresponding U.S. Pat. No. 3,413,389; Japanese Pat. No. U.M. 51696 and West German Patent No. 1504883.6). However, either the bead which is extruded has considerable hardness, and is difficult to insert in a retaining channel of a vehicle, or, if the extrusion is wholly of single or two hardness sponge rubber without any rubber of high density, there is difficulty in retention of the strip in the retaining channel and it will be found to be easily dislodged.
The main object of this invention is to provide improvements whereby a strip is much more easily inserted in a retaining channel than a strip having a solid rubber bead, but less likely to be dislodged therefrom than a strip comprising solely sponge or a combination of sponges.